Stop motion device for weft in the form of a single thread or several threads

ABSTRACT

Device with one thread responsive channel for each thread of a weft, each of said channels having means for providing an electrical signal in the presence of a thread, in which a channel used for a single-thread weft has means for providing an electrical signal in each of the channels used for a pluralthread weft in the presence of a thread whereby the function of a loom will be interrupted in the absence of a signal in any one of the channels.

O Umted States Patent 3,911,969

Rydborn Oct. 14, 1975 [5 STOP MOTION DEVICE FOR WEFF IN THE 3,526,254 9/1970 Schmitz 139/370 FORM OF A SINGLE THREAD OR 3,611,342 10/1971 Dieren et al... 66/163 R I THR 3,676,769 7/1972 Loepfe 139/370 UX SEVE EADS 3,688,958 9/1972 Rydborn I. 139/370 UX [76] Inventor: Sten Ake ()laus Rydborn, 3,802,469 4/1974 Loepfe 139/371 g i 343 00 Almhult, FOREIGN PATENTS OR APPLICATIONS we 325,838 7 1970 Sweden 139/370 [22] Filed: Nov. 6, 1973 1,184,583 3/1970 United Kingdom 139/370 [21] Appl' 4135308 Primary Examiner-James Kee Chi Attorney, Agent, or Firm-Br0wne, Beveridge, [30] Foreign Application Priority Data eGrandi & Kline Nov. 10, 1972 Sweden 14580/72 [57] ABSTRACT [52] US. Cl. 139/370; 28/51; 57/81; Device h one hread responsive channel for each 66/163; 340/259 thread of a weft, each of said channels having means [51] Int. Cl. D03D 51/34 o p o g an electrical signal in the presence of a [58 Field of Search 139/370, 371, 353, 122 W; thread, in which a channel used for a single-thread 28/51; 57/81; 66/163; 310/23,]; 340/259 weft has means for providing an electrical signal in each of the channels used for a plural-thread weft in [56] Ref Cited the presence of a thread whereby the function of a UNITED STATES PATENTS loom will be interrupted in the absence of a signal in 3,438,021 4/1969 Nelkin et a1. 310/8.1 UX any one of the channels 3,467,149 9/1969 Dosch et a1 139/371 4 Claims, 2 Drawing Figures PZ I P23 9 hHpHfiHp P22 P24 U.S,. Patent Oct. 14,1975 3,911,969

STOP MOTION DEVICE FOR WEFT IN THE FORM OF A SINGLE THREAD OR SEVERAL THREADS This invention relates to a stop motion device for weft in the form of a single thread or several threads, said device including multi-channel means interrupting the function of the loom upon rupture of the thread and having signal transmitter means in each channel, which convert the presence of the thread into an electric signal.

In prior, art devices of the type described several directional changes of the threads to be supervised are required, especially for the supervision of a single thread which, in order that the loom shall not stop, shall deliver a signal in two channels at the same time.

The present invention has for its object to provide a device which permits the desired supervision fundamentally by means of a single change of thread direction even though the thread shall deliver a signal in two channels at the same time.

This is realized according to the present invention in that in each channel of the stop motion device the signal transmitters means are connected to a first circuit means of high input impedance and low output impedance, and that signal transmitter means associated with common channels are connected to the first circuit means via a second circuit means of high input impedance and low output impedance.

The invention will be more fully described hereinbelow with reference to the accompanying drawing wherein FIG. 1 shows a circuit diagram of a weft stop motion device according to the invention; and, FIG. 2 shows the construction and relationship between three signal transmitters which may be used to supervise either a weft made of a single thread or a weft made of a plurality of threads.

For the supervision of weft in the form of a single thread or several threads, looms are provided with means having one channel for each thread of the weft. When the weft comprises two threads the means has two channels each with a signal transmitter converting the presence of the thread into an electric signal. In order that the means shall not interrupt the function of the loom there must occur a signal in each channel at the same time, which indicates the presence of the desired threads in the weft.

In many cases, however, it is desired to be able to supervise wefts consisting of several threads alternating with wefts having a single thread, without making greater modifications of the loom necessary. Hitherto, the single thread has been run in such a way as to actuate the signal transmitters of the various channels at the same time. As pointed out in the introduction, this has resulted in several changes of thread direction, which in turn leads to greater wear of the thread and considerably greater risk of rupture thereof.

In the circuitry illustrated in FIG. 1, these problems are solved in an extremely simple way. Connection A is a shielded connection, whereas connection B is a supply connection. Connection C leads to one channel of the said means which interrupts the function of the loom, while connection D leads to the second channel of the means. In order that the function of the loom shall not be interrupted, a signal must thus occur simultaneously in the two channels C, D.

Connection C leads to the output of a transistor amplifier stage including a transistor T2, said output being connected to connection A via a resistor R9, while 'connection D is connected to the output of a'tr'ansistor amplifier stage including a transistor T3, said latter output being connected to the'connection A via a resistor R12. The base of the transistor T2 is connected to two series connected signal transmitters P25 and PZ6, to the collector thereof via a resistor R7, and to'connection A via a resistor R8, while the base of the transistor T3 is connected to a pair of series-connected signal transmitters P27, P28, to the collector thereof via a' resistor R11, and to connection A via a resistor R10. The collector of the transistor T2 is connected to supply connection B via a resistor R2 and to connection A via a capacitor C2. The free connection of the signal transmitter PZS and the free connection of the signal transmitter PZ7 are connected to one another and to the output of an amplifier stage including a transistor T1, and to connection A via a resistor R6. The base of the transistor T1 is connected to four series-connected signal transmitters PZl, PZ2, P23 and PZ4, to the collector thereof via a resistor R4, and to connection A via a resistor R5. The free connection of the signal transmitter PZl is connected to connection A and to the collector of the transistor TI via a capacitor C1 and to the collector of the transistor T3 via a capacitor C3. Moreover, the collectors of the transistors T1 and T3 are connected to supply connection B via resistors R1 and R3, respectively.

Obviously, the three amplifier stages are identical and connected as emitter followers, whereby the amplifier stages will have a high input impedance and a low output impedance. If a thread gives rise to a signal in any of the signal transmitters PZl-PZZ the output signal from the transistor T1 will occur both at the input of the transistor T2 and the input of the transistor T3, a signal being thus obtained both in channel C and channel D. If a thread gives rise to a signal from the signal transmitter PZS or the signal transmitter PZ6, but to no signal in any of the signal transmitters PZ7 or P28, the signal will occur at the output C but not at the output D since the signal will be short-circuited via the amplifier stage including the transistor T1, which stage has a low output impedance, while the amplifier stage including the transistor T3 has a high input impedance as has the amplifier stage including the transistor T2. To obtain a signal on both connection C and connection D there is thus required a signal from any of the piezoelectric signal transmitters PZl-PZ4 or from both the piezoelectric signal transmitter PZS or PZ6. and P27 or P28.

As a result of this ingenious circuitry the signal transmitters PZ1-PZ8 can be optionally positioned as long as they are connected in the circuitry in the manner illustrated in the drawing. The present invention thus makes it possible to place the signal transmitter PZI beside the signal transmitters PZS and P27 as shown in FIG. 2, where the signal transmitters are provided with thread-receiving eyes 1, 2 and 3, and in the case of a single-thread weft to allow a thread to occur only in signal transmitter PZl, which gives rise to a signal'in both channel C and channel D. In another case, two threads of a weft can be supervised by allowing one thread to occur in signal transmitter P25 and the other thread in signal transmitter PZ7, thereby providing a signal both in channel C and channel D.

What I claim and desire to secure by Letters Patent 1. Weft stop motion device for interrupting the function of a loom upon rupture of one thread in a first weft formed of a plurality of threads or upon rupture of a thread of a second weft formed of a single thread, comprising a circuit having individual channel means for each of said threads, signal transmitter means in each of said individual channel means for converting the presence of said thread into an electric signal, said individual channel means for the single thread of said second weft being arranged to provide said electric signal in each of said individual channel means for each of the threads of said first weft.

2. A device as claimed in claim 1, wherein the signal transmitter means are piezoelectrical transmitters, and wherein all signal transmitter means are placed side by side.

3. A device as claimed in claim 1, wherein said individual channel means includes a circuit means of high input impedance and low output impedance, the inputs of said circuit means of each of said individual channel means of said first weft formed of a plurality of threads being connected to each other and the output of said circuit means of said individual channel means of said second weft formed of a single thread being connected to said connected inputs for the first weft.

4. A device as claimed in claim 3, wherein the circuit means consists of identical transistor amplifier stages connected as emitter followers. 

1. Weft stop motion device for interrupting the function of a loom upon rupture of one thread in a first weft formed of a plurality of threads or upon rupture of a thread of a second weft formed of a single thread, comprising a circuit having individual channel means for each of said threads, signal transmitter means in each of said individual channel means for converting the presence of said thread into an electric signal, said individual channel means for the single thread of said second weft being arranged to provide said electric signal in each of said individual channel means for each of the threads of said first weft.
 2. A device as claimed in claim 1, wherein the signal transmitter means are piezoelectrical transmitters, and wherein all signal transmitter means are placed side by side.
 3. A device as claimed in claim 1, wherein said individual channel means includes a circuit means of high input impedance and low output impedance, the inputs of said circuit means of each of said individual channel means of said first weft formed of a plurality of threads being connected to each other and the output of said circuit means of said individual channel means of said second weft formed of a single thread being connected to said connected inputs for the first weft.
 4. A device as claimed in claim 3, wherein the circuit means consists of identical transistor amplifier stages connected as emitter followers. 